Metallic Nanostructure Formation Using Self-Assembled Chemically Anchored Gold Nanoparticles

In the present work, the formation of silver nano-and mesopourous structures on highly oriented pyrolytic graphite (HOPG) modified with self-assembled gold nanoparticles (Au NPs) is demonstrated. To illustrate the patterning effect with nanometer resolution of Au NPs, a comparison between silver electrodeposition on bare HOPG (0001) substrate and Au NP-modified HOPG (0001) surface is performed. On bare HOPG substrate the electrodeposition occurs on terraces, steps, and surface defects according to the well known Volmer-Weber island growth mechanism. Whereas on the Au NP-modified HOPG substrate, silver deposition results in a very different morphology: nanostructures (mesoporous films for longer deposition time) are formed on the entire electrode surface. Field emission gun scanning electron microscopy, energy dispersive spectrometry and X-ray photoelectron spectroscopy are used to reveal the selective deposition of silver on Au NPs during the first stage of the electrodeposition process. At the later stage due to coalescence, mesoporous silver film is formed. The possible mechanism for silver ions penetration and reduction on single Au NP with n-dodecanethiol shell is discussed. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3517150] All rights reserved.